Of the Box

Extreme Laser Bursts Are Getting Us Closer to The Limitless Power of Nuclear Fusion

Creeping ever closer.

Achieving nuclear fusion without needing radioactive fuel or producing radioactive waste is now “within reach” thanks to a new laser-driven technique, according to researchers.

The type of fusion we’re talking about is hydrogen-boron fusion, which produces no neutrons and therefore no radioactivity in its primary reaction.

The downside, and part of what’s made it out of reach for scientists so far, is that it needs temperatures 200 times hotter than the core of the Sun to work properly.

Now an international team of scientists has come up with a method for using super-strength laser bursts to generate those kind of temperatures, compressing the hydrogen and boron nuclei together. We’re still a long way off a reactor, but we’re getting closer.

“It is a most exciting thing to see these reactions confirmed in recent experiments and simulations,” says lead researcher Heinrich Hora, from the University of New South Wales in Australia.

“Not just because it proves some of my earlier theoretical work, but they have also measured the laser-initiated chain reaction to create one billion-fold higher energy output than predicted under thermal equilibrium conditions.”

Fusion reactions have long been promising to give us a clean, limitless source of energy by taking the opposite approach to the nuclear fission reactions we rely on for some of our power today: instead of atoms being split, they’re combined together.

It’s similar to the reactions that power the Sun, as lighter nuclei are fused to build heavier ones with the help of incredible temperatures and pressures. As great as it sounds in theory, in practice it’s proving very difficult to harness.

But thanks to recent advances in laser technology, and both simulations and experiments run by Hora and his colleagues, the researchers think it might be possible to create an “avalanche” fusion reaction from a laser beam packing a quadrillion watts of power in just a trillionth of a second.

Diagram showing a hydrogen-boron reaction. (UNSW)

If future research doesn’t reveal any major engineering hurdles to this approach, the scientists reckon that a prototype reactor could be built within a decade.

The latest research also puts the hydrogen-boron approach ahead of other similar technologies, including deuterium-tritium fusion, which is being explored at the National Ignition Facility in the US (and also has the drawback of producing radioactive waste).

The team has put together a roadmap for further development of hydrogen-boron fusion, bringing us closer than ever before to the promise of cleaner nuclear fusion.

And while plenty of challenges remain in optimising the necessary reactions and keeping them stable enough to generate electricity, if this new fusion technique can be made to work, the benefits could be huge.

“The fuels and waste are safe, the reactor won’t need a heat exchanger and steam turbine generator, and the lasers we need can be bought off the shelf,” says Warren McKenzie, managing director of HB 11, which owns the patents to the new technology.